End-to-end Session Identifier in SIP (charter proposal )
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The end-to-end Session Identifier in an SIP-based multimedia communication
refers to the ability for endpoints, intermediate devices, and management and
monitoring system to identify and correlate SIP messages and dialogs of the same
higher-level end-to-end "communication session" across multiple SIP devices and
hops.  Unfortunately, there are a number of factors that contribute to the fact
that the current dialog identifiers as defined in SIP is not suitable for
end-to-end session identification.

Perhaps the most important factor worth describing is that in real-world
deployments devices like Session Border Controllers (SBC) often change the
current call identifiers (e.g., the From-tag and To-tag that are used in
conjunction with the Call-ID header to make the dialog-id) as the session
signaling passes through.

An end-to-end Session Identifier should allow the possibility to identify the
communication session from the point of origin, passing through any number of
intermediaries, to the ultimate point of termination. It should have the same
aim as the From-tag, To-tag and Call-ID conjunction, but should not be mangled
by intermediaries.

A SIP end-to-end Session Identifier has been considered as possible solution of
different use cases like troubleshooting, billing, session tracking, session
recording, media and signaling correlation, and so forth.  Some of these
requirements have also been identified and come directly from other Existing
working group within the RAI area (e.g. SIPRec, Splices).

Moreover, other SDOs have identified the need for SIP and H.323 to carry the
same "session ID" value(s) so that it is possible identify a call end-to end
even when performing inter working between protocols.

This group will first focus on a document that will identify, collect and
discuss all the requirements and the use cases that have been identified.

The document may identify the possibility to design a general mechanism or the
need to design multiple purpose built identifiers.

Once the needs are clear and identified, the working group will specify the
mechanism(s).

Specifically, the proposed working group will develop the following deliverable:

A requirement and use case document with key consideration for SIP Session
End-to-End identifier. The document will discuss the possibility of designing a
general mechanism or the needs to design multiple purpose build identifier.

Specification of new mechanism for SBC/B2BUA traversal.

Goal and Milestone:

October 2011 - Requirement and use case document sent to the IESG (Information)